Method of detecting temperature for controlling a refrigerator or a freezer

ABSTRACT

This invention relates to a method of detecting temperature for controlling a refrigerator or a freezer, and consists in that in order to detect a temperature in the refrigerator or freezer, vibration of cooling fin in the refrigerator or freezer produced from vibrating sounds of a compressor during operation, sounds of a refrigerating medium passing through cooling pipes, and rotating vibration sounds is utilized, that is, sounds above described are all transmitted to pickups through ice or frost formed therein at a temperature of 0* C. and by which the temperature of the refrigerator or freezer is electrically detected for controlling it.

Mi siemr'iel United States 1 Nijo [54] METHOD OF DETECTING TEMPERATURE FOR CONTROLLING A REFRIGERATOR OR A FREEZER [21] Appl. No.2 30,651

[52] US. Cl ..62/80, 62/140, 62/128, 62/151, 73/67.]

' [51] Int. Cl ..F25d 21/00 [58] FieldofSearch ..62/80, 128, 139, 140, 151

[56] References Cited UNITED STATES PATENTS 3,465,535 9/1969 Dodge ..62/l5l Feb. 15, 1972 Primary Examiner-William J. Wye Attorney-Polachek, Saulsbury & Hough [57] ABSTRACT This invention relates to a method of detecting temperature for controlling a refrigerator or a freezer, and consists in that in order to detect a temperature in the refrigerator or freezer, vibration of cooling fin in the refrigerator or freezer produced from vibrating sounds of a compressor during operation, sounds of a refrigerating medium passing through cooling pipes, and rotating vibration sounds is utilized, that is, sounds above described are all transmitted to pickups through ice or frost formed therein at a temperature of 0 C. and by which the temperature of the refrigerator or freezer is electrically detected for controlling it.

2 Claims, 3 Drawing Figures PATENTEDFEB 15 1912 SHEET 2 BF 2 INVENTOR. IKIYOICHI N/JO ATTDRN s METHOD OF DETECTING TEMPERATURE FOR CONTROLLING A REFRIGERATOR OR A FREEZER This invention relates to a method of detecting temperature in a refrigerator or a freezer, and particularly to a method for detecting a temperature for defrosting and automatic air conditioning of a refrigerator of a freezer.

The method of detecting a temperature in accordance with the present invention utilizes the effect of vibration of cooling fin in the refrigerator produced from vibrating sounds of a compressor during operation, sounds of a refrigerating medium passing through cooling pipes, and rotating vibration sounds of an air blower, which are all transmitted to pickups through ice or frost formed therein at a temperature of C. and by which the temperature of the refrigerator is electrically detected.

The invention will be illustrated in detail by way of example on an embodiment with reference to the drawing, in which:

FIGS. 1 and 2 are respectively side views of pickups for temperature detection.

FIG. 3 is a defrosting device in a refrigerator in which the method of the present invention has been applied.

In the first embodiment shown in FIG. I, numerals 1 denotes generally a known pickup which comprises a principal body 2, a vibration-absorbing plate 3 made of stainless substance, a vibrator rod 4 connecting said body 2 and said plate 3, and terminals A and B. Cooling fins for the refrigerator are shown at 5 in the figure holding said pickup l in position free from vibration in the refrigerator. The vibration absorbing plate 3 of the pickup l and the cooling fin 5 are located in opposite to each other with a space 6 therebetween. The cooling fin 5 is transmitted vibrating sounds of a compressor, passing sounds of a refrigerating medium through cooling fins, and rotating vibration sounds at all times during operation of the cooler while these vibrating sounds are not transmitted to the pickup I when the space 6 is existing between said vibration absorbing plate-3 and the cooling fin 5.

In accordance with the present invention, as the refrigeration is carried on and the temperature in the refrigerator reaches 0 C., the water in the air or water from a cooling load is frosted or frozen and the frost or ice produced are accumulated on the cooling fins. The thus produced frost or ice will fill the space 6 between said fin 5 and the vibration absorbing plate 3 whereby the vibration sounds which are transmitted to the cooling fin 5 are absorbed by the pickup 1 through the vibration-absorbing plate 3. As a consequence, the temperature of 0 C. in the refrigerator is electrically detected between terminals A and B ofthe pickup l.

The second embodiment shown in FIG. 2 is a device in which corrosion resistant water-contained material 7 such as a felt or the like is interposed between the vibration-absorbing plate 3 and the cooling fin 5, wherein other parts are identical with those of the embodiment described above and denoted with identical reference numerals. It may be apparent that in this embodiment the temperature of 0 C. can be detected in the similar manner as in the described first embodiment.

FIG. 3 illustrates the method of the temperature detection according to the invention which is applied in the defrosting device of the refrigerator. In the drawing, the refrigerating medium pipe is shown at 8. The cooling fins 5 are provided in said medium pipe 8. Pickups holded by shock absorber 9 are shown at la and 1b, one pickup 1a of which has its vibrationabsorbing plate provided with a space relative to the cooling fin adjacent to the inlet side 10 of the medium pipe 8, and another pickup lb has its vibration-absorbing plate near the outlet side ll of the medium pipe 8 provided with a space relative to the cooling fin 5, both being located in a position for preventing the vibration in the similar way.

A circuit for the operation of the device according to the method of the invention will now be described. As shown in FIG. 3, a defrosting control circuit E is connected between terminals A1, B1 and A2, B2 of pickups la, lb respectively. The terminals A1 and A2 are respectively connected to bases bl, b3 of transistors TRl and TR3 provided in relays L1 and L2. Collectors c1, c3 of the transistors TRl and TR3 are led to variable resistors R1 and R2, the outputs of which are led respectively to bases b2, b4 of the transistors TR2 and TR4, by which a current flowing between collectors c2, c4 and emitters e2, e4 of said transistors TR2 and TR4 is amplified. Between respective collectors c2 and c4 of the transistors TR2 and TR4 and terminals B1 and B2 of the pickups la and lb are respectively connected microrelays MLl and ML2 through sources 12a and 12b. In the drawing Cl and C2 show respectively condensers for preventing clattering due to pulsation, which are inserted in the microrelays MLI and ML2. X1, Y1 and X2, Y2 denote contacts for microrelays ML] and ML2, which are connected to sources 13 and 14 through the relay L3 having self-holding circuits S1 and S2. S3 and S4 denote the operation switches provided in said relay L3 for a cooler.

Operation of the defrosting device shown in FIG. 3 will be described. When the defrosting is started, the pickups la and lb are not transmitted vibration sounds from the cooling fin 5. Accordingly, the microrelays MLl and ML2 are not actuated and contacts X1, Y1 and X2, Y2 of which are closed, actuating the relay L3, by which the switches S3 and S4 for the cooler are closed for the cooling operation. Thus, cooling is carried on and cooling fin 5 are covered with ice or frost. The ice or frost will then fill the space 6 between the fin 5 and the vibration absorbing plate 2 of the pickups 1a which is provided in opposite to the cooling fin 5 in the vicinity of the inlet side 9 of the cooling medium pipe 8. In consequence, the vibration sounds of a compressor (not shown), vibration sounds of cooling medium passing through the cooling medium pipe 8, rotating vibration sounds of an air blower (not shown) are received by the pickup la through the cooling fin 5 so that the current flowing between the collector c4 and emitter e4 of the transistor TR4 in the relay L2 is amplified so as to actuate the microrelay ML2 and open the contacts X2 and Y2. In this position, as the self-holding circuits S1 and S2 in the relay L3 have been formed, the electric circuit connecting the source 13, relay L3, contacts X1, Y1 of microrelay MLl, and source 14 is closed. Thus, with the switches S3 and S4 for the operation of the cooler closed the cooling operation is carried on continuously and the cooling fins 5 are covered with ice or frost in the vicinity of the outlet sides 10 of cooling medium. When the space between the vibration-absorbing plate 2 of the pickup lb and the cooling fin 5 is filled with ice or frost, the described vibration sounds are absorbed by the pickup lb through the fin 5. The current flowing between the collector c2 and emitter e2 of the transistor TR2 in the relay L1 is amplified actuating the microrelay MLl so as to open the contacts X1 and Y1 and stop the action of the relay L3 so that switches S3 and S4 for operating the cooler is allowed to open and the cooling operation is fully stopped.

The frost will melt gradually as the temperature in the refrigerator rises. There is formed a space between the fin 5 and the vibration-absorbing plate 2 of the pickup lb in opposite to the cooling fin 5 in the vicinity of the output side 10 of cooling medium pipe 8. Consequently, the contacts X1 and Y1 of the microrelay MLl are closed and in this condition the self-holding circuits S1 and S2 of the relay L3 is opened. The relay L3 will not actuate, while the cooler will remain in stoppage and defrosting will continue. After the frost on the cooling fin 5 has been completely melted, there is formed a space between the cooling fins 5 and the vibration-absorbing plate 2 of the pickup 1a in opposite to the cooling fin 5 adjacent to the inlet side 10 of the medium pipe 8. Therefore, the microrelay M L2 will be actuated through the transistor TR4, the contacts X2 and Y2 being closed, and the relay L3 will be actuated to resume the cooling operation. The same operation is thus reciprocated in repetition.

Herein it is possible to apply such as soft rubber resistant to cold and chemical change between the cooling fin and the vibration absorbing plate of the pickup added with a material for lowering the freezing point including inorganic chemicals such as calcium chloride, magnesium chloride, and sodium chloride, and organic chemicals such as ethylene glycol, propylen glycol, diethyl glycol, triethylene glycol, triethyl glycol, glycerin, and acid acetate. By preferable selection of the kind and density of such material for lowering the freezing point a desired detector of temperature below C. could be obtained. By use of the pickup detector as described it is also possible to realize the defrosting and return operation for a low temperature freezer as well.

As may be clear from the above description, the method of temperature detection according to the invention provides a defrosting device which is capable of defrosting the refrigerator fully and automatically and serves for the preservation of a temperature, whereby the refrigerator can be completely defrosted and in which excessive rise of temperature in the refrigerator can be prevented. Thus the disadvantages of the conventional defrosting device that it will enter a cooling operation before the frost is not yet melted as seen in the intermittent cooling of the timer system or the timer will not work after the frost has been melted can well be eliminated. Therefore, the damages on the material in the refrigerator are avoided and the cooling effect is much elevated.

Substantially, the method of temperature detection in the refrigerator according to the present invention is to provide the pickups in the refrigerator opposite to an adequate member having a space therebetween and free from vibration, said adequate member being transmitted vibration from the vibrating sounds of a compressor, vibration sounds of medium, through the cooling pipe, and rotating sounds of the air blower, wherein the temperature of 0 C. can be detected electrically through ice or frost in said space. As the device can detect the temperature through the space which is filled with ice or frost produced at the temperature of 0 C., the terminals of the pickup can be directly connected to the electrical control circuit thereby allowing various controls adapted for the same course.

I claim:

l. A method of temperature detection for controlling a refrigerating device comprising employing a vibration-sensing means for detecting vibrations and converting the vibrations into a proportionate electrical impulse feedable into an electrical control circuit, placing the vibration-sensing means adjacent to and spaced from a solid surface frosted during a freezing operation, where said surface is transmittable of vibrations, frosting said surface sufficiently for a solid frost contact to exist between said surface and said vibrationsensing means, sensing vibrations from a refrigerator unit mechanically connected to said surface, directing an impulse reflecting detected vibrations from said surface through an electrical circuit from said vibration-sensing and vibrationtranslating means to a relay switch means responsive to said signal such that the refrigeration process is turned-off by said relay switch means.

2. A process according to claim 1, including defrosting frost from said surface sufficiently to eliminate vibration-transmitting frost connecting said surface to said vibration-sensing means, and responsive to said defrosting, ceasing and sending of electrical impulse signals representative of vibrations to said relay switch means such that said relay switch means switches-on said refrigeration operation. 

1. A method of temperature detection for controlling a refrigerating device comprising employing a vibration-sensing means for detecting vibrations and converting the vibrations into a proportionate electrical impulse feedable into an electrical control circuit, placing the vibration-sensing means adjacent to and spaced from a solid surface frosted during a freezing operation, where said surface is transmittable of vibrations, frosting said surface sufficiently for a solid frost contact to exist between said surface and said vibration-sensing means, sensing vibrations from a refrigerator unit mechanically connected to said surface, directing an impulse reflecting detected vibrations from said surface through an electrical circuit from said vibration-sensing and vibration-translating means to a relay switch means responsive to said signal such that the refrigeration process is turned-off by said relay switch means.
 2. A process according to claim 1, including defrosting frost from said surface sufficiently to eliminate vibration-transmitting frost connecting said surface to said vibration-sensing means, and responsive to said defrosting, ceasing and sending of electrical impulse signals representative of vibrations to said relay switch means such that said relay switch means switches-on said refrigeration operation. 